Answer to Practice Exercise

Initial Observation

The observation is that the bush died over the winter.

Preliminary Conditions

There were two theories posed:

A₁: The bush was planted in a spot that exposed it to too much cold, specifically deep frost killed the roots before they were sufficiently established.
A₂: Grubs from a beetle attacked the roots during winter and killed it.

Both theories have merit since they satisfy at least half of the criteria for a scientific theory (it will be required to show this starting with the next set of examples). Also, both theories could explain the initial observation (as briefly explained above).

Data

D₁: The roots were soft and spongy
D₂: No signs of larvae in the soil.

Evaluation Chart

	Frost	Grubs
Soft & Spongy Roots	yes	no
No Larvae	yes	no

Result

From this data (frost - 2, grubs - 0), it would seem that frost killed the roots.